In an announcement on its official blog today, Twitter said that "photos just got more social." What has actually happened is that social just got more photos. In an update to both iOS and Android mobile apps, Twitter will allow users to tag each other in photos, with the ability to upload four photos at once starting on iOS and coming to Android and the web "soon."

Users will be able to tag up to ten other people in their photos, while maintaining all 140 characters for brief, micro-blogged commentary.

Making Android-powered cameras isn't something new for Polaroid, but that doesn't mean it's the first company to come to mind when thinking of capturing digital photos (and for good reason). On the other hand, the company's old instant printing cameras call upon an altogether different set of memories. So now the company is shaking things up by re-introducing the premise it's known for. Not only can the Socialmatic instantly share pictures to social networks like any other Android-toting camera out there, it can instantly print them out to a 2"x3" sheet of paper.

It's one thing to release an app for Android, but if a developer doesn't keep it up with the times, its usefulness is limited. So Diigo has now updated its Android app to version 2.0, bringing in a desperately needed makeover. The social bookmarking app can now handle notes, pictures, messages, and bookmarks in an interface that won't make anyone whose two-year contract hasn't expired cringe.

It's been a pretty big year for Instagram. So far, it has released several big new features including video and people tagging. To end 2013 on a high note, Instagram announced today that it is launching Instagram Direct - a new private sharing feature. Highlights include:

The ability to share photos privately with up to 15 people.

See who has seen, liked, and commented on your privately-shared photo in real time.

The presence of Google+ is definitely growing as it continues to become a significant part of how we interact with many of Google's services. Early this year, the social network branched out to become a sign-in solution for virtually any kind of app or website. With an announcement yesterday, Google+ is now set up to accept sign-ins from Google Apps users and accounts without an actual Google+ profile. If that weren't good enough, the permission system has been greatly improved to support "incremental auth," which allows apps and websites to request only vital permissions to begin using them, and then ask for new permissions once the user is logged in.

It was over a year ago that Google started adding custom URLs to Google+, but the unwashed masses still haven't gotten them. The simplified addresses have been restricted to Googlers and a few select people/brands so far, but no longer. Google is expanding Google+ custom URLs to most users over the next few days.

A vanity URL won't be automatic when a new Google+ page is created – there are some preconditions before Google will let you ditch the string of numbers.

YouTube is awesome, but it's anti-social. You create a video in isolation, upload it to your personal channel, and wait for the inevitable flood of ego-shattering comments. If someone does happen to like your work, they will copy the link and share it on Facebook, Google+, or any other social network where good words are occasionally tolerated, and you may never hear their feedback. MixBit is a more social experience, one where friends can work on videos together from the comfort of their mobile devices.

One of the problems of living in modern times is that it's easy for us to shut ourselves off from our communities, living in a place for years without ever meeting the Smiths down the road or the Patels across the street. If you've wished for a way to resolve this issue that doesn't require the awkwardness of knocking on your neighbor's door, you're in luck, because there's now an app for that.

It's been three and a half years since Angry Birds was first released and you thought it was finally over. You disconnected your internet, set up your shack in the woods, and you're living off the land without ties to the metal world. It's over, right? There are no more birds to be flung. They can't touch you here. At last, you can relax, send a carrier pigeon to the two friends who still talk to you and invite them over for a tree bark barbecue.

Pocket, in an update to celebrate the one year anniversary of Read It Later's rebrand, has introduced (among other things) Send to Friend, a new feature that allows for quick, easy sharing of content with friends. Users can accept shared content directly from the Pocket app, using the app's new Inbox. Those sharing can also highlight quotes or add their own comments before sharing, sending them along for friends to read.